dpkg --list | grep i386
dpkg --status [package]
dpkg --search [file]
dpkg --listfiles [package]
apt-get upgrade never installs new packages and never remove existing packages.
apt upgrade never removes existing packages but might install new packages. It also upgrades kernel packages and kernal image if any.
apt full-upgrade upgrades packages and kernel packages. It might install new packages or remove existing ones if it is necessary for the ugrade.
apt-key add [pgp-key]
apt-key del [id]
nmcli device wifi list
nmcli connection show
nmcli device wifi connect [ssid] password [password]